Registration Dossier

Administrative data

Key value for chemical safety assessment

Toxic effect type:
dose-dependent

Effects on fertility

Description of key information

According to information requirements, a reproduction /developmental toxicity screening test was performed, where rats were administered molybdenum disilicide by oral route. No adverse effects were observed up to the highest tested dose. NOAEL: > 1000 mg/kg bw/day.

Link to relevant study records
Reference
Endpoint:
screening for reproductive / developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2019
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)
GLP compliance:
yes
Limit test:
yes
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
A total of 64 male and 64 female Wistar rats were randomly divided into four groups (15 rats/sex/group)
Route of administration:
oral: gavage
Vehicle:
CMC (carboxymethyl cellulose)
Details on exposure:
Test item was given through oral gavage, in graduated doses of 100, 300, and 1000 mg/kg b. wt./day, to three groups of male and female rats. The control group received vehicle only.
Duration of treatment / exposure:
Male rats were treated for 43 days. Female rats were treated for two weeks prior to mating, variable time to conception, the duration of pregnancy and 14 days after delivery.
Dose / conc.:
100 mg/kg bw/day (nominal)
Dose / conc.:
300 mg/kg bw/day (nominal)
Dose / conc.:
1 000 mg/kg bw/day (nominal)
Control animals:
yes, concurrent vehicle
Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
not specified
Clinical biochemistry findings:
not specified
Urinalysis findings:
not specified
Behaviour (functional findings):
not specified
Immunological findings:
not specified
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
not examined
Neuropathological findings:
not specified
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
not specified
Other effects:
no effects observed
Description (incidence and severity):
No treatment related effect on thyroid hormone (T3, T4 and TSH) was observed in adult rats
Reproductive function: oestrous cycle:
not specified
Reproductive function: sperm measures:
not specified
Reproductive performance:
not specified
No treatment related effect on implants, pre-natal loss, percent pre-natal loss, post-natal loss, percent post-natal loss, mating index, male fertility index, female fertility index, gestation index, parturition index, pre-coital interval, percent of pregnant females, and duration of gestation was observed.
No treatement related effect on litter size, sex ratio, mean estrus cycle length and mean number of estrus cycle prior to mating was observed.
Key result
Dose descriptor:
NOEL
Effect level:
>= 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Remarks on result:
not determinable due to absence of adverse toxic effects
Clinical signs:
not examined
Dermal irritation (if dermal study):
not examined
Mortality:
not examined
Body weight and weight changes:
not examined
Food consumption and compound intake (if feeding study):
not examined
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
not examined
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined
Other effects:
not examined
Reproductive function: oestrous cycle:
not examined
Reproductive function: sperm measures:
not examined
Reproductive performance:
not examined
Remarks on result:
not measured/tested
Critical effects observed:
no
Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
not specified
Clinical biochemistry findings:
not specified
Urinalysis findings:
not specified
Sexual maturation:
not examined
Anogenital distance (AGD):
no effects observed
Nipple retention in male pups:
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings:
no effects observed
Other effects:
no effects observed
Description (incidence and severity):
No treatment related effect on thyroid hormone (T3, T4 and TSH) was observed in PND 4 and 14 pups.
Behaviour (functional findings):
not specified
Developmental immunotoxicity:
not specified
Key result
Dose descriptor:
NOEL
Generation:
F1
Effect level:
>= 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
not specified
Remarks on result:
not determinable due to absence of adverse toxic effects
Critical effects observed:
no
Clinical signs:
not examined
Dermal irritation (if dermal study):
not examined
Mortality / viability:
not examined
Body weight and weight changes:
not examined
Food consumption and compound intake (if feeding study):
not examined
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Sexual maturation:
not examined
Anogenital distance (AGD):
not examined
Nipple retention in male pups:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
not examined
Histopathological findings:
not examined
Other effects:
not examined
Behaviour (functional findings):
not examined
Developmental immunotoxicity:
not examined
Remarks on result:
not measured/tested
Critical effects observed:
no
Reproductive effects observed:
no
Treatment related:
no
Conclusions:
The No Observed Adverse Effect Level (NOAEL) for parental toxicity was 1000 mg/kg b. wt./day based on the absence of treatment related adverse effect in parent male and female rats at the highest tested dose level (i.e., 1000 mg/kg b. wt./day dose level).
The NOAEL for reproductive and fertility toxicity was at 1000 mg/kg b. wt./day dose level based on the absence of treatment related adverse effect in parental male and female rats.
Effect on fertility: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
1 000 mg/kg bw/day
Study duration:
subacute
Species:
rat
Effect on fertility: via inhalation route
Endpoint conclusion:
no study available
Effect on fertility: via dermal route
Endpoint conclusion:
no study available

Effects on developmental toxicity

Description of key information

According to information requirements, a reproduction /developmental toxicity screening test was performed, where rats were administered molybdenum disilicide by oral route. No adverse effects were observed up to the highest tested dose. NOAEL: > 1000 mg/kg bw/day.

Effect on developmental toxicity: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
1 000 mg/kg bw/day
Study duration:
subacute
Species:
rat
Effect on developmental toxicity: via inhalation route
Endpoint conclusion:
no study available
Effect on developmental toxicity: via dermal route
Endpoint conclusion:
no study available

Justification for classification or non-classification

According to the available information, no classification for reproduction / developmental toxicity is deemed necessary for molybdenum disilicide.